Moen produces a variety of Single Handle faucets. The interior components and assembly are not the same for each model. This article will explain one of the most common handle assemblies referred to as an Adapter. This mechanism was introduced in 1996 and was used on a select group of products through 2009. The characteristics of the mechanism include a handle rotation range of 180 degrees and a flat cap on the top or red and blue round plug button. This faucet style utilizes a 1225 cartridge.